Method and means of determining the health condition of a living creature

ABSTRACT

A method of determining the health condition of a living creature comprises the steps of detecting a selected physiological characteristic, e.g. the conductivity of the skin, of the living creature at a statistically significant plurality of measuring points distributed over a defined body portion of the living creature, determining, e.g. by means of a computer, the statistical distribution of the measured values and comparing the statistical distribution of the measured values to a reference statistical distribution of the selected physiological characteristic. The said reference statistical distribution is a logarithmic distribution which is determined according to the calculating methods of statistics by means of the computer directly from the measured values obtained for the individual tested living creature. The invention for the first time permits a reliable indication as to overall health condition of a human or animal.

The invention relates to a method and a means of determining the healthcondition of a living creature on the basis of a comparison of aselected measured physiological characteristic of the living creature toa corresponding reference characteristic of the healthy condition.

The invention relates in particular to a method and a means of makingpossible an indication as to the overall health condition of a human oranimal.

All instruments employed in medical diagnosis acquire a specificcharacteristic or specific parameter of a patient, e.g. pulse frequency,blood pressure, chemical composition of the blood etc. Since the normalranges are known from the corresponding measured values of a healthypopulation, a criterion for the nature and severity of an illness can beestablished from the deviation of the actual values from the standard.The diagnosis is made from a plurality of different characteristics,medical experience being the determining factor in selecting thecharacteristics in each case. However, until now it has not beenachieved to establish explicit and objective criteria for the "overallhealth" condition of a patient even by means of "alternative" methods.

Accordingly it is an object of the present invention to provide a methodand means of the aforementioned kind which permit a reliable indicationas to the overall health condition of a test person. In addition, theinvention is intended to permit establishing to what degree thecondition of the test person deviates overall from an ideal condition.The means are also intended to permit economic examination of a largenumber of test persons by enabling the examination to be made quicklyand cost effectively.

The method according to the invention is characterized by the steps ofdetecting the selected physiological characteristic at a statisticallysignificant plurality of measuring points distributed over a definedbody region of the living creature, determining the statisticaldistribution of the measured values obtained for the said body region,and comparing the statistical distribution of the measured values to areference statistical distribution in the form of the logarithmic normaldistribution of the selected physiological characteristic. It isparticularly advantageous and thus preferred to determine the saidlogarithmic distribution from the measured values obtained for thetested person. Due to it being easily available the skin of the testperson is preferably used as the body region in question, the electricalconductivity of the skin or its radiation intensity being taken as thephysiological characteristic. However, the invention is restrictedneither to such special physiological characteristics nor to the bodyregion "skin". Instead, the method according to the invention isgenerally applicable also to other characteristics and other suitableinternal or external body regions.

The invention makes use of the fact that according to the rules ofstatistics, parameters irrespective of which kind always follow aspecific statistical distribution (viz. L. Sachs: StatischeAuswertungsmethoden, 2nd Edition, Springer Verlag Berlin 1969, pages105-106), "statistical distribution" being understood to mean theprobability function p(x) indicating the probability or frequency ofencountering a specific measured value x in an arbitrary test object,whereby x can encompass the total scale of values available.

The physiological characteristics of living creatures such as, forinstance, body height, blood pressure, drug tolerance etc. are alsoalways distributed according to a logarithmic normal distribution, thereason for this being assumed a multiplicative configurational principle(viz. e,g, also: H. Gebelein and H. J. Heite, Klin. Wschr. 28 (1959),page 41). Within the framework of tests according to the invention itwas further established that the logarithmic normal distribution existsnot only for a specific characteristic in measurements made on aplurality of individuals, but also for a single healthy individual whenthe characteristic concerned is measured on a sufficiently large numberof measured values of the individual. "Sufficiently" in this contextmeans no further significant change occurring in the resultingstatistical distribution when the number of measured values is furtherincreased.

The ideal log-normal distribution of such measured values obtainablefrom a single test person exists only when the ideal "multiplicativeconfiguration principle"--i.e. the combined effect of all sub-units inspace and time in the sense of an ideal organization--is satisfied.Therefore, by comparing the statistical distribution, as measured or asdetermined by suitably transforming the measured values, to thelogarithmic normal distribution an explicit classification of the"overall" condition with reference to the condition of an idealbiological organisation can be obtained. Further indications in thisrespect can be obtained in addition to the comparison when according tofurther embodiments of the invention the deviations of the same order,e.g. the relative differences of the moments of the first to nth orderare determined and/or the change in the statistical distribution withtime is established and subjected to a correlation analysis. Thetemporal development of the statistical distribution describes thedynamic behaviour of the network of internal dependencies forming thebasis of the measurement. The correlation analysis (e.g. factoranalysis) enables the internal relationships between the skin areas tobe described dynamically for a known assignment of the measured values,these relationships including all interrelationships with the organs.

From this it follows that in the sense of the invention a test person isable to be classified "overall" as being "healthy" when his distributionfunction p(x) does not significantly deviate from p_(n) (x), where p(x)represents the measured distribution function and p_(n) (x) the idealdistribution function for a healthy individual. This distributionfunction p_(n) (x) is a logarithmic normal distribution and can beestablished according to the invention from the measured values of thetest person, i.e. it not being necessary to obtain the normaldistribution as an empirical function of the measured values of aplurality of healthy test persons.

Inversely the "illness condition" in this "overall" sense can be definedby the systematic (and fully) listed deviations between the functionsp(x) and p_(n) (x). One salient advantage of the method according to theinvention is, among other things, that there is no need to recourse toestablishing the measured values of a plurality of test persons, but tocalculate the ideal distribution function applicable to the individualtest person directly from the measured values and to compare it to theactual statistical distribution.

In accordance with a further aspect of the invention a means ofimplementing the method according to the invention is provided whichincludes a sensor arrangement for detecting a selected physiologicalcharacteristic of the living creature at a plurality of measurementpoints distributed over a body region and outputting correspondingsignals, means for processing the signals output by the sensorarrangement, and means for calculating from the signals output by saidsignal processing means the actual statistical distribution and thelogarithmic normal distribution of the signal-related measured values ofthe physiological characteristic obtained. Obtaining the measured valuesis particularly uncomplicated and speedy when according to a furtherembodiment of the invention the sensor arrangement includes a pluralityof contact or proximity sensor elements distributed over a definedsurface area as well as a means of successively scanning them. Asregards further embodiments of the invention reference is made to theclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be explained in more detail with reference to anexample and the drawing in which.

FIGS. 1a, 1b shows the statistical distribution of the conductivityvalues of the skin of a patient before treatment (FIG. 1a) and aftertreatment (FIG. 1b) as compared to the logarithmic normal distributionemploying the same mean values and variances in each case.

FIGS. 2a, 2b shows the ratio of the moments of the rth order (r=1. . .6) for a logarithmic normal distribution and a measured distributionbefore treatment (FIG. 2a) and after treatment (FIG. 2b).

FIG. 3 is a block diagram of a means of obtaining the conductivity ofthe skin and for processing the obtained measured values according toone embodiment of the invention

FIG. 4 is a section view showing the sensor member of a sensorarrangement of the means according to FIG. 3 and

FIG. 5 is a view of the sensor arrangement according to FIG. 3 as seenfrom below.

DETAILED DESCRIPTION OF THE DRAWINGS

With reference first to FIGS. 3-5 one embodiment of a means or anapparatus for implementing the method according to the invention willnow be described on the basis of measuring the electrical conductivityof the skin of a patient. The means includes according to FIG. 3 asensor arrangement 1, a signal processing means 2 and a processor 3.

The sensor arrangement 1 can be a multichannel electrode comprising asensor member 4 and a scanner member 5. The sensor member 4 is shown inmore detail in FIGS. 4 and 5 and includes a plurality of needle-shapedelectrodes or sensor elements 13 located longitudinally shiftable in abase member. Each sensor element 13 is assigned a spring to preload thesensor element in its initial position as shown in FIG. 4 in which thefree ends of the sensor elements 13 protruding from the base member arelocated in a plane which may be flat or curved in accordance with thecurvature of a bodily region, e.g. of the hand to be tested of a testperson. The preloading of the sensor elements 13 causes them to exert adefined pressure on the skin surface when brought into contacttherewith. An "adequate" number of sensor elements 13 is provided, ithaving been established that a number between 50 and 150, e.g. 60 sensorelements 13 is adequate in the aforementioned sense.

The sensor elements 13 are further distributed over a defined e.g.circular measurement area 14 of the sensor member 4. The scanner member5 of the sensor arrangement 1 which can be of a type as generally knownto the person skilled in the art, serves to successively scan theindividual sensor elements 13 and to furnish the signals characterizingthe conductivity values obtained at the individual sensor elements 13 tothe processing means 2. The measurement values obtained may be e.g."pointer drops" of "electroacupuncture" methods as usual nowadays whichresult as soon as the measurement electrode is applied to themeasurement point with constant contact pressure on the basis of amaximum value.

The signal processing means 2 includes an amplifier 6 for amplifying theindividual signals output by the sensor arrangement 1. The output of theamplifier 6 is connected to a bypass filter 7 which has the effect offiltering out any noise signals from the measurement signals. Thefiltered measurement signals are then applied to an. AD converter 8. Thedigital output signals of the AD converter 8 are passed via an interface9 of the signal processing means 2 to a processor 3. In this way theprocessor 3 receives digital signals which are amplified and free ofnoise, these signals corresponding to the measurement signalsestablished by the sensor arrangement 1.

In addition, the signal processing means 2 includes a means of applyinga defined reference AC voltage to a suitable body location of the testperson. If the measured values are obtained on one side of the hand ofthe test person, a suitable measurement point for applying the referencevoltage is the other side of the hand. The means for applying thereference voltage includes a voltage generator 10, the output of whichis furnished to a suitable hand electrode 12 via a variable amplifier11.

The processor 3 establishes from the signals output by the processor 2the logarithmic normal distribution p_(n) (x) corresponding to themeasurement values obtained from and initially applicable to the testperson, i.e. the ideal distribution function of the latter and,furthermore, the real distribution function p(x). The logarithmix normaldistribution is that which has the same mean value x and the samedispersion σ as the measured distribution p(x). From the deviationsbetween p(x) and p_(n) (x) an indication is possible as to the natureand scope of the health problems involved.

The processor 3 also establishes other parameters characteristic of thehealth condition of the test person such as e.g. the ratio of themoments of the rth order of the logarithmic normal distribution to themeasured statistical distribution. The result of the computations can bedisplayed on a computer monitor and/or printed out in the form of graphsor tabulated data. The processor 3 also handles localization andcomputation of the maximum conductivity value within the measuredmatrix.

Computation of the measured distribution function p(x) and thelogarithmic normal distribution p_(n) (x) is explained in the followingon the basis of an example computation in which the numerical values arethose as tabulated in Table 1.

Example computation

1. Dividing the frequency values into n classes, whereby in this casen=14. The class mean values are given over the full measurement range(as stated in Tab. 1) as 4, 12, 20, 28, . . . ,108 in steps of 8 (as thex axis of FIG. 1a, b shows). In the following these values areidentified k_(m) (i) where i=1, . . . ,14. For example k_(m) (2)=12,k_(m) (3)=20.

2. Computation of the measured distribution p(x)

a) Computation of the sum of the frequency values (p(x)) given inTable 1. As an example the values before treatment are given.

The sum stated N in the following is ##EQU1##

Thus N=0+14+22+34+18+32+2+0=122

The frequency values P(x) are then divided by the sum N ##EQU2##

Expressed as an equation: ##EQU3##

This measured distribution is depicted as a bar graph.

3. Computation of log normal distribution

Computing central value x and dispersion σ: ##EQU4##

EXAMPLE ##EQU5##

All values of p_(n) (x_(i)) are then summed over all i's and divided bythe total sum. This total sum ##EQU6## so that e.g. at the mark 68 isnot 0.121 but according to this standarization ##EQU7##

EXAMPLE

On a patient seriously afflicted with bronchial asthma the electricalconductivity values were established at 112 measurement points on theskin and the relative frequency of the values entered on a scale from 0to 100.

The frequencies at which the values in the various scale ranges weremeasured are listed in Table 1 for n=8 measurement intervals. Theleft-hand column relates to the values prior to treatment, those in theright to the values following relatively successful treatment (patientsuffered less).

The data itself indicates neither an objective criterion for the healthcondition of the patient prior to treatment nor the degree ofimprovement following treatment, whereas when testing the frequencies p(n ) in obtaining specific values of conductivity n as to theiragreements with the logarithmic normal distribution (represented inFIGS. 1a and 1b by the solid line curve) we then find:

1) Before treatment there are significant deviations from the normaldistribution (FIG. 1a) as well as in the deviations of the moments ofthird and higher order (FIG. 2a) defined as ##EQU8##

This indicates that the patient is not healthy, the nature andseriousness of the affliction being recognizable in this projection asthe nature and degree of deviation from the logarithmic normaldistribution.

2) Following treatment both a significantly better agreement with thelogarithmic normal distribution (fig. 2b) and also a lesser deviation ofthe higher order moments from the ideal moments of the normaldistribution are recognizable, the curves being transformed so that themoments of the first and second order (averages and variances) of theideal and measured distribution agree.

    ______________________________________                                                       treatment                                                                       before    after                                              Measurement range                                                                              frequencies                                                                             frequencies                                        ______________________________________                                         0-48             0         0                                                 48-56            14        15                                                 56-64            22        34                                                 64-72            34        34                                                 72-80            18        30                                                 80-88            32         8                                                 88-96             2         1                                                  96-112           0         0                                                 ______________________________________                                    

Up until now the invention has been described on the basis of measuringthe electrical conductivity of the skin as the physiologicalcharacteristic. When other characterics are made use of the means of theinvention must be modified accordingly. For example, the intensity withwhich the skin radiates in the infrared or optical range can be utilizedas the characteristic. In this case proximity sensor elements are usedpreferably in an arrangement and number corresponding to that of theneedle-shaped sensor elements of the embodiment already described. Othermeans for sensing the physiological characteristics can take the form ofgrid, roller or brush-type electrodes. Although, in addition, the abovedescribes in particular the preferred assessment of the overall healthcondition of a test person on the basis of comparing the realdistribution function to the ideal, i.e. logarithmic normal distributionof the measured values obtained from the test person, the invention isunderstood to also cover a comparison on the basis of a referencestatistical distribution of the data established for the physiologicalcharacteristic in question from measurements made on a number of healthyindividuals.

I claim:
 1. A method of determining the health condition of a particular test individual on the basis of a comparison of a selected measured physiological characteristic of the test individual to a corresponding reference characteristic of a healthy condition comprising the steps of: detecting values of the selected physiological characteristic at a statistically significant plurality of measuring points distributed over a defined body region of the test individual, determining a statistical distribution of the detected values obtained for the body region of the test individual, determining a logarithmic reference normal distribution of the detected values, and comparing the statistical distribution of the detected values to the logarithmic reference normal distribution of the detected values Of the selected physiological characteristic.
 2. A method according to claim 1, wherein a region of the skin of the test individual is employed as the body region.
 3. A method according to claim 2, wherein the physiological characteristic to be measured is the conductivity of the skin to which a specific electric potential is applied.
 4. A method according to claim 2, wherein the physiological characteristic to be measured is radiation intensity of skin.
 5. A method according to claim 1, wherein deviations of the same order are determined from the comparison.
 6. A method according to claim 1, wherein the statistical distribution is subjected to a correlation analysis.
 7. A method according to claim 1, wherein deviations of frequencies of occurrences of the same orders of values are determined from the comparison.
 8. An apparatus for determining the health condition of a particular test individual on the bases of a comparison of a selected measured physiological characteristic of the test individual to a corresponding reference characteristic of a healthy condition, said apparatus comprising:a sensor device comprising a plurality of sensing elements for detecting values of the selected physiological characteristic of the test individual at a plurality of measurement points distributed over a body region of the test individual; a processing means coupled to the sensor device for processing signals representative of the detected values of the physiological characteristics received from the sensor device; said processing means including a calculating processor means for calculating from the signals an actual statistical distribution of the detected values and for calculating a logarithmic normal distribution of the measured values.
 9. An apparatus according to claim 8, wherein said sensor device includes a plurality of sensor elements distributed over a defined surface area of said body region and a means for successively scanning said sensor elements.
 10. An apparatus according to claim 9, wherein said sensor elements include needle-shaped elements.
 11. An apparatus according to claim 8, wherein said sensor device comprises sensor elements for obtaining the measured values by proximity.
 12. An apparatus according to claim 8, wherein said sensor device includes electrodes arranged in a grid to detect the values of the physiological characteristic. 